Abstract: In a method for heating an exhaust system of a combustion engine of a motor vehicle, the exhaust system comprises at least two components for exhaust gas cleaning. For at least one component, a temperature regulation is provided for heating the component while using a heating operation mode. For the heating of the exhaust system, a heating operation is used via a pulse control with heating pulses (101) and heating pauses (102), which switches between a heating operation mode and a normal operation without heating measures.

Abstract: A method for monitoring a nitrogen oxide storage catalyst in an exhaust system of an internal combustion engine, in which a reduction of nitrogen oxides is carried out by means of a reducing agent is disclosed. During a regeneration of the nitrogen oxide storage catalyst, the following steps are carried out: A measurement is carried out, from which a slip rate of the reducing agent not absorbed in the nitrogen oxide storage catalyst is ascertained. In addition, at least one expected value for the slip rate of the reducing agent is ascertained from at least one model. Subsequently, a computation of a monitoring variable is carried out by means of the slip rate of the reducing agent ascertained from the measurement and the at least one expected value for the slip rate of the reducing agent. Finally, a diagnosis of the storage capacity of the nitrogen oxide storage catalyst is carried out on the basis of the monitoring variable.

Abstract: In a method for heating an exhaust system of a combustion engine of a motor vehicle, the exhaust system comprises at least two components for exhaust gas cleaning. For at least one component, a temperature regulation is provided for heating the component while using a heating operation mode. For the heating of the exhaust system, a heating operation is used via a pulse control with heating pulses (101) and heating pauses (102), which switches between a heating operation mode and a normal operation without heating measures.

Abstract: A method for monitoring a nitrogen oxide storage catalyst in an exhaust system of an internal combustion engine, in which a reduction of nitrogen oxides is carried out by means of a reducing agent is disclosed. During a regeneration of the nitrogen oxide storage catalyst, the following steps are carried out: A measurement is carried out, from which a slip rate of the reducing agent not absorbed in the nitrogen oxide storage catalyst is ascertained. In addition, at least one expected value for the slip rate of the reducing agent is ascertained from at least one model. Subsequently, a computation of a monitoring variable is carried out by means of the slip rate of the reducing agent ascertained from the measurement and the at least one expected value for the slip rate of the reducing agent. Finally, a diagnosis of the storage capacity of the nitrogen oxide storage catalyst is carried out on the basis of the monitoring variable.

Abstract: In a method for diagnosing an SCR catalyst system of an internal combustion engine, the SCR catalyst system comprises at least one first SCR catalyst device (20) and at least one second SCR catalyst device (30). A first injection position upstream of the first SCR catalyst device (20) in the form of a first metering device (40) is provided for injecting liquid reducing agent for the SCR catalyst devices (20, 30). A second injection position between the two SCR catalyst devices (20, 30) in the form of a second metering device (50) is furthermore provided. Both SCR catalyst devices (20, 30) are monitored in a differentiated way by means of active and passive diagnostic methods.

Abstract: In the case of a method for operating an exhaust gas aftertreatment system of a motor vehicle, the exhaust gas aftertreatment system comprises at least one NOx storage catalyst (10) and at least one SCR catalyst (30). According to the invention, when an inadequate function of the NOx storage catalyst (10) or of the SCR catalyst (30) is identified, at least one auxiliary measure is initiated which leads to a reduction of the NOx emissions of the motor vehicle.

Abstract: In a method for the diagnosis of an exhaust gas aftertreatment system for an internal combustion engine, the exhaust gas aftertreatment system comprises at least one NOx storage catalytic converter (10) and at least one SCR catalytic converter (30) which is arranged downstream of the NOx storage catalytic converter (10). According to the invention, a regeneration of the NOx storage catalytic converter (10) is blocked and/or interrupted in order to improve the frequency and/or quality of the diagnosis of the SCR catalytic converter (30).

Abstract: In the case of a method for checking the plausibility of a NOx sensor (62; 63) in an SCR catalytic converter system having at least one first SCR catalytic converter device (20) and having at least one second SCR catalytic converter device (30) and having in each case one dosing point (40, 50) for a reducing agent solution for the SCR catalytic converter devices (20, 30) upstream of the respective SCR catalytic converter device, the NOx sensor (62) to be checked for plausibility is situated either between the first SCR catalytic converter device (20) and the second SCR catalytic converter device (30), or the NOx sensor (63) to be checked for plausibility is situated downstream of the second SCR catalytic converter device (30).

Abstract: In the case of a method for operating an exhaust gas aftertreatment system of a motor vehicle, the exhaust gas aftertreatment system comprises at least one NOx storage catalyst (10) and at least one SCR catalyst (30). According to the invention, when an inadequate function of the NOx storage catalyst (10) or of the SCR catalyst (30) is identified, at least one auxiliary measure is initiated which leads to a reduction of the NOx emissions of the motor vehicle.

Abstract: In a method for the diagnosis of an exhaust gas aftertreatment system for an internal combustion engine, the exhaust gas aftertreatment system comprises at least one NOx storage catalytic converter (10) and at least one SCR catalytic converter (30) which is arranged downstream of the NOx storage catalytic converter (10). According to the invention, a regeneration of the NOx storage catalytic converter (10) is blocked and/or interrupted in order to improve the frequency and/or quality of the diagnosis of the SCR catalytic converter (30).

Abstract: In the case of a method for checking the plausibility of a NOx sensor (62; 63) in an SCR catalytic converter system having at least one first SCR catalytic converter device (20) and having at least one second SCR catalytic converter device (30) and having in each case one dosing point (40, 50) for a reducing agent solution for the SCR catalytic converter devices (20, 30) upstream of the respective SCR catalytic converter device, the NOx sensor (62) to be checked for plausibility is situated either between the first SCR catalytic converter device (20) and the second SCR catalytic converter device (30), or the NOx sensor (63) to be checked for plausibility is situated downstream of the second SCR catalytic converter device (30).

Abstract: In a method for diagnosing an SCR catalyst system of an internal combustion engine, the SCR catalyst system comprises at least one first SCR catalyst device (20) and at least one second SCR catalyst device (30). A first injection position upstream of the first SCR catalyst device (20) in the form of a first metering device (40) is provided for injecting liquid reducing agent for the SCR catalyst devices (20, 30). A second injection position between the two SCR catalyst devices (20, 30) in the form of a second metering device (50) is furthermore provided. Both SCR catalyst devices (20, 30) are monitored in a differentiated way by means of active and passive diagnostic methods.